Phosphorus containing polymers

ABSTRACT

New compositions of matter which are reaction products of a phosphate ester containing active groups such as -OH, -NH2 and SH and sufficient phosphorus trihalide or phosphorus oxyhalide to produce a polymer which is used as a fire retardant in plastic compositions.

United States Patents Cohen et al. 5] May 23, 1972 54] PHOSPHORUS CONTAINING [56] References Cited POLYMERS UNITED STATES PATENTS [72] Inventors: Margalit Cohen; Kenneth E. MacPhce,

both of Guelph, Ontario Canada 2,372,244 3/1945 Adams et a1 ..260/2 P [73] Assignee: Uniroyal, Ltd., Montreal, Quebec, Canada FOREIGN PATENTS OR APPLICATIONS [22] Filed: F b- 19, 19 0 935,926 9/1963 Great Britain ..260/2 P 21 App]. No.: 12,858

Przmary Examiner-Samuel H, Blech Attorney-Thomas A. Beck [52] US Cl ..260/2 P, 424/78, 252/498,

252/499, 252/351, 252/357, 260/2.5 R, 260/2.5 57 TR! A], 260/16, 260/17, 260/30.6 R, 260/47 P, 260/79, 1 ABS CT 260/857, 260/858, 260/860, 260/865, 260/874, New compositions of matter which are reaction products of a 260/876 R, 260/880 R, 260/887, 260/893, 260/897 phosphate ester containing active groups such as OH, 260/944, NH and -SH and sufficient phosphorus trihalide or 260/948, 260/950, 260/ 953 phosphorus oxyhalide to produce a polymer which is used as a [5 l 1 Int. Clfire retardant in plastic compositiong [58] Field of Search ..260/2 P, 79

14 Claims, No Drawings PHOSPHORUS CONTAINING POLYMERS BACKGROUND OF THE INVENTION 1. Description of the Prior Art United States Pat. No. 2,372,244 states that the reaction of trihydroxyalkyl phosphates with chlorinating agents such as phosphorus trichloride causes a replacement of the hydroxyl group with a halogen and not a phosphorylation of the polyol as in the present invention.

British Pat. Nos. 927,175, 925,570 and 935,926 disclose the use of reaction products of phosphorus trichloride or phosphorus oxychloride with glycols or tris(hydroxymethyl) phosphine oxide for manufacturing polyurethane products.

2. Summary of the Invention The present invention relates to a novel phosphorus containing polymer composition which is formed by the reaction of phosphorus oxyhalides or phosphorus trihalides and a phosphorus polyol or phosphate ester containing active groups such as OH, NH and SH. The phosphorus polyol is formed by the reaction of phosphoric acid with an alkylene oxide.

It has been determined that the reaction products of the present invention vary, depending upon whether a 1:1, 1:2 or 1:3 molar ratio of phosphorus trihalide or oxyhalide to phosphorus polyol is used. It appears that the reaction products comprise phosphate polymers, phosphate-phosphite polymers and phosphate-phosphonate polymers which are thought to be highly cross-linked when a 1:1 mole ratio of reactants is used. The 1:2 mole ratio of reactants presumably produces a product which has a certain amount of cross-linking, but not as much as the product resulting from the 1:1 ratio.

The phosphorus halides used as one of the reactants in the present invention have the general formula:

wherein X is chlorine, bromine, or iodine, R is chlorine, bromine, iodine, alkyl, aryl, alicyclic, alkoxy or aryloxy, and Z is oxygen or nothing. Examples of suitable phosphorus halides are phosphorus oxychloride, phosphorus oxybromide, phosphorus trichloride, phosphorus tribromide or 'any phosphorus dichloride.

The phosphorus polyols used as the other reactant in accordance with the present invention may be prepared according to U.S. Pat. No. 2,372,244 which is hereby incorporated by reference herein, and have the formula:

wherein R R and R are the same or different and are alkylenes or chloro-, bromoor iodomono-substituted alkylenes which have two to eight carbon atoms, n is an integer from 1 to 10, preferably 1 to 1.5, and X is O, S, or NH and Z is oxygen or nothing. An especially preferred phosphorus polyol is tris(hydroxychloropropyl) phosphate.

As disclosed in U.S. Pat. No. 2,372,244 noted, the phosphorus polyols used in the present invention are prepared by reacting a phosphorus acid with an alkylene oxide.

The phosphorus acids used in the preparation of the phosphorus polyol are those acids corresponding to a P equivalency of from about 72 to 95 percent. Representative acids include phosphorous acid, 100 percent phosphoric acid, pyrophosphoric acid, polyphosphoric acid, various metaphosphoric acids, various partial esters of said acids and mixtures of any of the above acids and/or esters. It is essential that the acids selected have a P 0 equivalency of from about 72 percent to about percent. 1f the acid has a P 0 equivalency of substantially less than 72 percent, water will be present and react with alkylene oxide to form undesired glycols.

The alkylene oxides which are reacted with the aforementioned acids to form a phosphorus polyol contain an oxirane ring. Suitable alkylene oxides include ethylene oxide, propylene oxide, the isomeric and normal butylene oxides, hexylene oxides, octylene oxides, dodecene oxides, methoxy and other alkoxy propylene oxides, styrene oxide or substituted styrene oxide and cyclohexene oxide'or substituted cyclohexene oxide.

Halogenated alkylene oxides may also be used such as epichlorohydrin, epiiodohydrin, epibromohydrin, 3,3- dichloropropylene oxide, 3-chloro-l ,2-epoxypropane, 3- chloro-l ,2-epoxybutane,- l-chloro-2,3-epoxybutane, 3 ,4-

dichlorol ,2-epoxybutane, 1,4-dichloro-2,3-epoxybutane, and 3,3,3-trichloropropylene oxide. Mixtures of any of the above alkylene oxides may also be employed. The reaction products of all acids and alkylene oxides noted above result in the formation of phosphorus polyols which can be used in the practice of the present invention.

The reaction of the phosphorus halide and phosphorus polyol may be carried out either in the presence or absence of a solvent. If a solvent is used it is preferably a polar solvent which includes but is not limited to hydrocarbon or chlorinated hydrocarbon solvents such as chlorobenzene etc. The reaction is conducted at a temperature of from about 25 to 180 C., preferably 80 to C. for a period of 30 minutes to 30 hours. During the reaction period, it is necessary to maintain an inert gas atmosphere in the reaction vessel. Such gases as nitrogen, carbon dioxide or any other inert gas may be effectively used for this purpose.

Any residual hydrogen chloride gas formed during the reaction is removed from the reaction mixture by heating under vacuum after the reaction is complete.

It is believed that the polymeric products of the present invention are the result of a reaction between a halogen of the phosphorus halide or oxyhalide and an available hydrogen present in the phosphorus polyol. The exact structure resulting from any particular reaction is not certain. As noted previously there are polymeric phosphates present along with polymeric phosphate-phosphite, polymeric phosphatephosphonate compounds, and possibly some cyclization products which result from the reaction. It is preferable to avoid specific structures for the products of this invention and therefore these products are characterized by hydroxyl number, phosphorus content, and viscosity.

The products of the present invention are useful as fire retardants in polyurethane, polyester, or thermoplastic materials, in textiles, in foams, in coatings and in laminates. The phosphorus containing polymers may also be used as surface active agents, antistatic agents, fuel or lubricant additives, plasticizers for synthetic resins, insecticides, etc.

The following examples serve to illustrate the invention. All temperatures are given in degrees Centigrade.

EXAMPLE 1.

Preparation of polyhydroxychloropropyl phosphate by reacting tris(hydroxychloropropyl) phosphate (polyol) with phosphorus oxychloride in molar ratio of 3: l

Tris(hydroxychloropropyl phosphate)(ll, 442.6 g., 0.9 moles) formed by reacting phosphoric acid and epichlorhydrin at a 1:4 ratio so that n 1.33) is added to a 2-liter flask equipped with a thermometer, reflux condenser, dropping funnel with dip tube, and a nitrogen purge. Phosphorus oxychloride (42.2 g., 0.3 mole) is added slowly over a l-hour period. The temperature of the reaction mixture is slowly raised from ambient to 50 and held at this temperature for 2 hours, then increased gradually over the next hour to 130- The reaction mixture is then heated at this temperature for an additional 2 to 8 hours or until no more hydrogen chloride is evolved. Residual hydrogen chloride is removed by heating the product at 140 under vacuum mm. Hg) for 1 hour. Product:

Viscous liquid-457.3 g.

% Phosphorus-7.6, calc. 8.0

Hydroxyl number-157, calc. 164

EXAMPLE 2 Preparation of polyhydroxychloropropyl phosphate by reacting polyol with phosphorus oxychloride in molar ratio of 2:1.

Tris(hydroxychloropropyl) phosphate (11, 421.7 g., 0.86 mole) is heated from ambient temperature to 50 in a flask equipped as in example 1 and the reaction mixture maintained at this temperature for 2 hours during the addition of 67.0 g. (0.43 mole) of phosphorus oxychloride. During the next hour the reaction mixture is heated to 100 and held at this temperature for about hours.

The residual hydrogen chloride is removed from the product at 20 mm. Hg and 100 during 1 hour.

Product:

Very viscous liquid443.0 g.

% Phosphorus-8.5, calc. 8.9

Hydroxyl number93, calc. 105

EXAMPLE 3 Preparation of highly cross-linked polyhydroxychloropropyl phosphate by reacting polyol with phosphorus oxychloride in molar ratio of 1:1.

EXAMPLE 5 Preparation of polyhydroxychloropropyl phosphate-phosphite by reacting polyol with phosphorus trichloride in molar ratio of 2: l.

The preparation is carried out using the procedure described in example 4 except that 356.6 g. (0.72 mole) oftris (hydroxychloropropyl) phosphate (11, n 1.33) is reacted with 49.5 g. (0.36 mole) phosphorus trichloride.

Product:

Amber viscous liquid380 g.

Brookfield viscosity at 32 C. 1 60,000 cps.

Brookfield viscosity at 50 C. 1 30,000 cps.

% Phosph0rus8.8, calc. 9.9

Hydroxyl numberl34, calc. l 12 EXAMPLE6 Preparation of highly cross-linked polyhydroxy- TABLE I.-PROPERTIES OF PHOSPHORUS CONTAINING POLYMERS Products E 1 Reactants OH Number P, percent 'lvg'iscolsigyid e N ll l b zll Polyol Moles Halide Moles Cale. Found Cale. Found 32 821d 1 Tris(hydi'oxychloropropyl)phosphate- 3 P001: 1 164 157 8.0 7. 6 2 do 2 P0011 1 105 03 8.1) 8,5 1 POC13 1 0 11.4 8.0

3 PCla 1 220 175 8.3 7. 0 40,000 (8,000) 2 PC]; 1 112 134 0.9 8.8 160,000 (130,000) 1 P013 1 0 11.8 10.0 680,000 (100,000)

Phosphorus oxychloride l l l g., 0.71 mole) is added drop- As noted previously, the addition of a phosphorus containwise to 350 g. (0.71 mole) of the tris(hydroxychloropropyl ing polymer of the present invention to a thermoplastic or phosphate) (11, n 1,33) as d rib d in xa l 1, at roa thermosetting matrix polymer results in afire resistant blend. t ratu durin a 24 i d, D i th next 40 to 60 The flame resistant thermoplastic or thermosetting matrix minutes the temperature of the reaction mixture is increased p y [Such as p ly r p y thanes (both polyether gradually to 90 100 whereupon the reaction mixture gels. and Polyester ABS T651115 (g and blends), p y p d nyl resins such as polyvinyl chloride, polystyrene etc. and Dark amber gel-400 g. polyethylene and polypropylene] must contain sufficient Phosphorus8.0, calc. 1 1.4 phosphorus containing polymer so that the blend possesses a phosphorus content between about 0.1 and 10 percent based EXAMPLE 4 on the total weight of the blend. Thus the actual amount of Preparation of p y y y p py p p p phosphorus containing polymer to be added to the blend will phite by reacting polyol with phosphorus trichloride in molar vary depenlmg upon the phosphorus i i h x ratio 3:1. In many instances, the polymer matrix is self-extinguishing Phosphorus trichloride (30 3 g 0 22 mole) is added to but the additives which are added to the polymer for various 324.5 g. (0.66 mole) tris(hydroxychloropropyl phosphate) (11, reasons. calls? the i j to The polxmcrs of the n 1.33) as described in example 1, during a 4-hour period. prlesem ii also mhlblt any S.uch flammapihty ql The reaction is exothermic and the y g chloride is said additives when blended with an additive-containing evolved immediately. After addition of phosphorus trichloride mamx polymeli' Any convenient known method can be used to blend the is completed, the reaction mixture is agitated for 1.5 hours, then heated gradually to 120 during thenext 60 minutes and matrix p f and the phosphorus contammg polymer of thc present invention. ci g i iz zz sg 22;; 231 323 ;f z i iii ggg The following examples illustrate blends of various matrix chloride is removed at 20 mm. Hg. and during 1.5 hours. polymers and the polymers of the present invcmion' Product: 70

Brookfield viscosity at 32 C.40,000 cps. I Brookfield viscosity at 50 C.-8,000 cps. Polyester casting containing polyhydroxychloropropyl Phosphorus-7.9 calc. 8.3 phosphate. Hydroxyl number-175, calc. 220 An alkyd is prepared using the following reactants:

Tetrachlorophthalic anhydride 1.05M Fumaric anhydride 0.95M Ethylene glycol 2.20M

The alkyd is blended with styrene (30 pph.) and the result ing unsaturated polyester contains 21 percent chlorine.

A polyester casting is prepared from 175 parts of said polyester, 3.5 parts benzoyl peroxide paste and 17 parts polyhydroxychloropropyl phosphate (product of example 2).

This casting tested by A.S.T.M. D-1692-59T continues to burn for 28 seconds after removal of the flame and therefore is classed as non-burning. The same casting shows a burning rate of'ri; in./min. when tested by A.S.T.M. D757 (Globar).

Polyester castings prepared without polyhydroxychloropropyl phosphate continue to burn 4 minutes and 25 seconds after removal of the flame when tested by A.S.T.M. D-1692-59T.

The results of these burning tests are summarized in table 11.

EXAMPLE 8 Polyester casting containing polyhydroxychloropropyl phosphate-phosphite.

A polyester casting is prepared by admixing 175 parts polyester (having a composition described in example 7), 3.5 parts benzoyl peroxide paste and 17 parts polyphosphatephosphite ester (prepared in example 4).

The results ofthe burning tests are summarized in table II.

EXAMPLE 9 Polyester casting containing polyhydroxychloropropyl phosphate-phosphite.

A polyester casting is prepared as described in example 7 except that 17 parts of the polyhydroxychloropropyl phosphate-phosphite described in example is substituted for the product of example 2. The results of the burning tests are presented in table 11.

EXAMPLE 10 Polyester casting containing highly cross-linked polyhydroxychloropropyl phosphate-phosphite.

A polyester casting is prepared as described in example 7 except that 17 parts of the phosphorus containing polymer described in example 6 is substituted for that described in example 2. The results of the burning tests are presented in table 11.

TABLE 11 Flammability Tests of Polyester Castings Utilizing Phosphorus Containing Polymers Preparation of semi-flexible polyurethane foam utilizing polyhydroxychloropropyl phosphate-phosphite.

A semi-flexible polyurethane foam was prepared using methods known to those skilled in the art, by reacting the following compounds:

Parts 3,000 mol. wt. triol, polyether-based 1900 (Dow Voranol CP 3001 260 mol. wt. triol 10.0

(Dow Voranol CP 260) 33% triethylene diamine in dipropylene glycol 4.0

(Houdry Dabco 33 LV) Dibutyl tin dilaurate 3.5

(M & T Corp. D 22) Water 4.0 Silicon 1.0

(Union Carbide L 5320) Reaction product of Example 4 30.0 (8.2%) Polymeric isocyanate 124.0

Mobay Mondur MR The resultant material was molded and cut into strips and its flammability tested.

The foam did not shrink and had good flame resistance. It was self-extinguishing according to ASTM D-1692-59T and had a burning rate of0.6 in./min.

Polyurethane foam prepared without the product of example 4 burned readily at a rate of 1.5 in./min. when tested by ASTM D- l 692-59T.

EXAMPLE 12 Preparation of rigid polyurethane foam using polyhydroxychloropropyl phosphate-phosphite.

A rigid polyurethane foam was prepared using methods known to those skilled in the art by reacting the following compounds:

Parts Reaction product of Example 4 100.0 (42%) Silicone 1.5

(Union Carbide L-5320) 33% triethylene diamine in dipropylene glycol (Houdry Dabco 33 LV) 10.0 Dibutyl tin dilaurate 5.0

(M 81. T Corp. D-22) Water 4.0 Polymeric isocyanate 1 18.0

Mobay Mondur-MR The foam did not shrink and was non-burning according to ASTM D-1692-59T.

Rigid foam prepared using Voranol CP 3001 instead of the phosphorus containing polymer (example 4) in the above formulation burned readily at a rate of 5.7 in./min. when tested by ASTM D-1692-59T.

EXAMPLE l3 Flame retardant thermoplastic resin containing polyhydroxychloropropyl phosphate-phosphite.

A non-burning flexible polyvinyl chloride (PVC) containing flammable plasticizers is prepared from:

Polyvinyl chloride parts (Uniroyal Marvinol VR-22) Di-isooctyl phthalate 45 parts Phosphite chelator (Mark C Argus) 6 parts Nepheline syenite (filler) 24 parts Reaction product of Example 4 15 parts (7.5%)

The components are milled together on a two-ro1l mill at about The resulting composition is molded into strips 6 in. in length, 5 in. in width and 0.125 in. in thickness. Strips (2 X 5 in.) cut from the molded composition are then subjected to ASTM D-1692-59T flame retardance test. The results are reported in table [11.

EXAMPLE 14 Flame retardant thermoplastic resin containing polyhydroxychloropropyl phosphate-phosphite.

A non-burning flexible polyvinyl chloride containing flammable plasticizers is prepared from:

Polyvinyl chloride l parts (Uniroyal Marvinol VR-22) Di-isooctyl phthalate 55 parts Phosphite chelator Mark C Argus 6 parts Nepheline syenite (filler) 24 parts Reaction product of Example 10 parts (5.1%)

Strips are prepared from the milled and molded composition as described in example 13 and are then subjected to ASTM D-l692-59T flame retardance test. The results are reported in table Ill.

EXAMPLE l5 Flame retardant thermoplastic resin containing polyhydroxychloropropyl phosphate-phosphite.

A non-burning flexible polyvinyl chloride containing flammable plasticizers is prepared from:

Strips are prepared from milled and molded composition as described in example 13 and are then subjected to ASTM D- l692-59T flame retardance test. The results are reported in table "I.

EXAMPLE 16 Flame retardant acrylonitrile-butadiene-styrene resin containin g polyhydroxychloropropyl phosphate-phosphite.

This phosphorus containing polymer is obtained by reacting tris( hydroxychloropropyl) phosphate with phosphorus trichloride in molar ratio of 3:2. The preparation is carried out as in example 4.

Following the milling and molding procedure of example 13, fire retardant acrylonitrile-butadiene-styrene resin (ABS) samples are prepared from 100 parts Uniroyal Kralastic MH 1801 and parts or 13.1 percent polyhydroxychloropropyl phosphate-phosphite, prepared as described in the previous paragraph.

The samples are tested by a modified ASTM burning test. In order to prevent dripping of the melted sample, ASTM Test D-l692-59T is modified by placing the sample on a sheet of asbestos paper (size 2.25 X 5 in., with 90 folds A in. wide along each 5 in. side).

Results of the flammability test are reproducible and comparable, and are presented in table III.

TABLE Ill Flammability of Thermoplastic Materials Containing Polyhydroxychloropropyl Phosphate-Phosphite Phosphorus Time Example Matrix containing ASTM until lnches Polymer Polymer Method extingremain uishing PVC D-l692-59T 52 sec. 4.0 13 PVC from Ex. 4 D-l692-59T 32 sec. 4.2 l4 PVC from Ex. 5 D-l692-59T 33 sec. 4.3 15 PVC from Ex. 6 D-l692-59T 15 sec. 4.3

ABS D-l692-59T 15 min. 1.6

modified 36 sec. l6 ABS from Ex. l6 D-l692-59T 5 min. 3.7

modified 44 sec.

Having thus described the invention what we claim and desire to protect by Letters Patent is:

l. A phosphorus containing polymer which comprises the reaction product of:

A. a phosphorus halide having the general formula:

wherein X is chlorine, bromine or iodine, R is chlorine, bromine, iodine, alkyl, aryl, alicyclic, alkoxy, or aryloxy, and Z is oxygen or nothing; and

B. a phosphorus containing ester having the formula:

wherein R R and R are selected from at least one of the group consisting of alkylene compounds having two to eight carbon atoms and halogen substituted alkylene compounds having two to eight carbon atoms, n is an integer between I and 10, X is selected from the group consisting of O, -S, or NH or mixtures thereof, and Z is oxygen or nothing;

wherein the molar ratio of reactants of (A) and (B) respectively is between 111 and 1:3.

2. The polymer of claim 1 wherein n in (B) is between 1 and 1.5.

3. The polymer of claim 2 wherein (A) is phosphorus oxychloride and (B) is tris(hydroxychloropropyl) phosphate.

4. The polymer of claim 2 wherein (A) is phosphorus trichloride and (B) tris(hydroxychloropropyl) phosphate.

5. The polymer of claim 2 wherein (A) is phosphorous tribromide and (B) is tris(hydroxychloropropyl) phosphate.

6. The polymer of claim 2 wherein (A) is phosphorus oxybromide and (B) is tris(hydroxychloropropyl) phosphate.

7. The polymer of claim 2 wherein (A) is phosphorus oxychloride and (B) is tris( hydroxyethyl) phosphate.

8. The polymer of claim 2 wherein (A) is phosphorus trichloride and (B) is tris(hydroxyethyl) phosphate.

9. The polymer of claim 2 wherein (A) is phosphorus tribromide and (B) is tris( hydroxyethyl) phosphate.

10. The polymer of claim 2 wherein (A) is phosphorus oxybromide and (B) is tris( hydroxyethyl) phosphate.

11. The polymer of claim 2 wherein (A) is phosphorus oxychloride and (B) is tris(hydroxypropyl) phosphate.

12. The polymer of claim 2 wherein (A) is phosphorus trichloride and (B) is tris(hydroxypropyl) phosphate.

13. The polymer of claim 2 wherein (A) is phosphorus tribromide and (B) is tris(hydroxypropyl) phosphate.

14. The polymer of claim 2 wherein (A) is phosphorus oxybromide and (B) is tris(hydroxypropyl) phosphate. 

2. The polymer of claim 1 wherein n in (B) is between 1 and 1.5.
 3. The polymer of claim 2 wherein (A) is phosphorus oxychloride and (B) is tris(hydroxychloropropyl) phosphate.
 4. The polymer of claim 2 wherein (A) is phosphorus trichloride and (B) tris(hydroxychloropropyl) phosphate.
 5. The polymer of claim 2 wherein (A) is phosphorous tribromide and (B) is tris(hydroxychloropropyl) phosphate.
 6. The polymer of claim 2 wherein (A) is phosphorus oxybromide and (B) is tris(hydroxychloropropyl) phosphate.
 7. The polymer of claim 2 wherein (A) is phosphorus oxychloride and (B) is tris(hydroxyethyl) phosphate.
 8. The polymer of claim 2 wherein (A) is phosphorus trichloride and (B) is tris(hydroxyethyl) phosphate.
 9. The polymer of claim 2 wherein (A) is phosphorus tribromide and (B) is tris(hydroxyethyl) phosphate.
 10. The polymer of claim 2 wherein (A) is phosphorus oxybromide and (B) is tris(hydroxyethyl) phosphate.
 11. The polymer of claim 2 wherein (A) is phosphorus oxychloride and (B) is tris(hydroxypropyl) phosphate.
 12. The polymer of claim 2 wherein (A) is phosphorus trichloride and (B) is tris(hydroxypropyl) phosphate.
 13. The polymer of claim 2 wherein (A) is phosphorus tribromide and (B) is tris(hydroxypropyl) phosphate.
 14. The polymer of claim 2 wherein (A) is phosphorus oxybromide and (B) is tris(hydroxypropyl) phosphate. 